10 CALIFORNIA CITRUS CULTURE. 
LOCAL CLIMATIC CONDITIONS. 
As regards the lability to frost, we can not be too cautious in select- 
ing a locality for a citrus grove. True, the orange (the lemon is a 
little more susceptible to frost than is the orange) will resist a tem- 
perature a little below freezing, perhaps as low as 26 degrees Fahr. 
if not too long continued, but if the thermometer goes down to 22 
degrees or 25 degrees Fahr. above zero, both fruit and tree are likely 
to suffer. This is the more true if the cold endures for quite a long 
period, and if the sun comes out clear the following morning the 
damage is increased. It is found in California, as elsewhere, that the 
cold is more pronounced in lower levels, so that it is safer to locate 
higher up on the mesas. The cold, hke water, flows down into the 
lower valleys, so that often the lower groves will suffer harm, while 
those higher up escape all damage. It is a gratifying fact that seriously 
cold seasons do not oceur in California on an average oftener than about 
one year in four. 
FROST PREVENTION. 
As a question of permanent public policy, it is uncertain how far 
protection against frost, by artificial means, may wisely be carried; 
but where orchards are already planted, it is surely unwise to neglect 
the insurance that is afforded by a proper equipment for frost pro- 
tection. The cost will be great, and the labor involved in the fight 
will be both disagreeable and exhaustive, when the cold nights come. 
But when not only the fruit but the trees themselves are at stake, the 
orchardist can not afford to take any chance. In one large lemon grove 
the expenditure of $6,000 fighting frost in the winter of 1911-12 saved 
$100,000 worth of fruit. While the year following, when the cold 
reached a temperature of 15 degrees above zero, it cost twice as much 
to save the crop. Yet at this time not only the fruit was saved, but 
irreparable damage to the trees was prevented. Many would have been 
killed outright, others greatly injured. 
Prior to 1911, for years, the coal baskets, one to each tree were 
successfully used in frost protection. The experience in 1911 proved 
that oil pots were preferable to coal baskets. Oil as a fuel is more 
